Extensible trencher tooth



Sept. 10, 1957 R. L. JORDAN 2,805,495

EXTENSIBLE TRENCHER TOOTH Filed May 27, 1954 2 sheets sheet 1 INVENTOR.ROBERT L. JORDAN %ww A /M/ Sept. 10, 1957 R. L. JORDAN 2,805,496

EXTENSIBLE TRENCHER TOOTH Filed May 27, 1954 2 Sheets-$heet 2 iiiINVENTOR. ROBERT L. JORDAN A 7' TORNEY United St EXTENSIBLE TRENCHERTOOTH Robert L. Jordan, Sacramento, Caiif.

Application May 27, 1954, Serial No. 432,680

1 Claim. (Cl. 37-442) My invention relates to improvements in teeth fortrenching and digging machines and more particularly to teeth havingcutting blades which may be extended to compensate for wear.

In the operation of trenching and digging machines one of the majorcauses of inoperative periods or unproductive down time is the necessityfor changing the blades of the teeth on the buckets. Owing to theabrasive action of the dirt, rocks and soil being dug, the bladesquickly become worn to a short length, thereby reducing the machinescutting efficiency or rendering it inoperative. Attempts have been madeto correct this, the attempts having usually been directed towardreducing blade wear by making the blades of very high quality, carefullyheat treated steel and alloys. While this to some extent has overcomethe difiiculty of blade wear, yet the cost of these high grade bladesbecomes a substantial expense item and even with the very best blades,wear takes place at a considerable rate and replacement becomesnecessary, with its attendant down time. The replacement of old wornblades by new blades consumes a substantial amount of time during whichfixed costs and labor costs continue. While considerable effort has beenexerted in this field to reduce blade replacement time, for example, bythe use of special adapters and pockets and other types of bladeholders, and which have to some extent reduced replacement time, yet sofar as is known all of these special and relatively costly blade holdersand adapters require the use of the expensive varieties of blades andthe kinds of blades which must be discarded when worn. None of them, asa matter of common knowledge in the art, utilizes a relativelyinexpensive blade and a blade which quickly can be extended outwardly tonew blade position and thus outlast the expensive types of blades.

It is therefore an object of my invention to provide an extensibletrencher tooth which, as the blade becomes worn, effects by means of avery simple and rapid operation, the positioning of the blade to alocation such as would be occupied by a new blade.

It is another object of my invention to provide an extensible trenchertooth which may quickly and easily be installed and removed fromtrencher buckets of the kinds commonly used.

It is still another object of my invention to provide an extensibletrencher tooth which is economical to manufacture and which may beinstalled and the blade extended with the use of very simple hand toolsand by unskilled labor.

It is yet another object of my invention to provide an extensibletrencher tooth which provides a positive lock on the blade and whichthus prevents the blade being forced inwardly by the ground.

It is a still further object of my invention to provide an extensibletrencher tooth wherein the blade employed does not need to be of thehighest quality steel or alloy and heat treated in an expensive manner.

Other objects, together with the foregoing, are at- Patented Sept. 10,1957 tained in the embodiment of the invention described below andillustrated in the accompanying drawings, in which:

Figure 1 is a side elevation in semi-diagrammatic form of a trencherwheel having buckets thereon and showing a number of the trencher teethinstalled on the buckets. A portion of the figure is broken away toreduce the extent of the figure.

Figure 2 is a perspective of the extensible trencher tooth.

Figure 3 is a section along a substantially median vertical,longitudinal plane of the tooth shown in Figure 2 in installed positionon a bucket edge.

Figure 4 is a perspective of the blade clamping member.

Figure 5 is a perspective similar to the view shown in Figure 2 buthaving a portion of the upper part of the body broken away to show aworn blade in recently extended and locked position and having a portionof the blade broken away to show a portion of the clamping member inblade clamping position.

Trenching machines or ditching machines or trenchers, as they arevariously known, are customarily either of the ladder type or of thewheel type. In Figure 1 a portion of a trencher of the wheel type isshown, the trencher tooth of my invention, however, being equally usableon the ladder type, the trencher machine (not shown) having projectingfrom the rear end thereof a supporting arm 6 having mounted thereon arotatable power-driven wheel 7. Mounted around the perimeter of thewheel 7 is a plurality of buckets 8 secured to the wheel perimeter, asby fastenings 9. The buckets commonly in use assume a variety of formsbut the form illustrated is typical and comprises a back wallllienlarged at its inner edge to form a mounting bracket 11 andprojecting radially from the perimeter of the wheel, with the wall it}being curved forwardly in the direction of rotation of the wheel, asshown by the arrow 12, to form a bottom wall 13terminating at itsleading extremity in a leading edge 14 whichfrequently is taperedforwardly and inwardly to a point 15. Extending from both sides of theback' wall 16 to the wheel perimeter are side walls 16 and which withthe other walls of the bucket and the wheel perimeter form a bucket-likecavity or pocket into which loosened earth 17 spills as the excavatingbucket revolves, the buckets being emptied near the top of their travelinto a suitable chute or conveyor. As the wheel 7 rotates, the trenchingmachine proceeds forwardly in a direction indicated by the arrow 18, thecombined movement causing each succeeding bucket to scoop up anadditional amount of earth, as indicated by the numeral 21.

Mounted around the edge of each of the trencher buckets is a pluralityof trencher teeth 22, the teeth being distributed not only along theback wall 10 of the bucket but along the side walls 16 as well. Theteeth disposed on the side walls 16 define the trench width by cuttingthe soil on the sides of the trench, the side teeth moving in asubstantially vertical plane. In operation, it is customary for theblade of the trencher tooth to extend forwardly in the direction ofmotion of the blade and to be inclined slightly outwardly, as mostclearly appears in Figure 1. The outermost point or tip of the blade iscustomarily adjusted so as to protrude slightly beyond the plane of theouter side of the tooth for in this position the blade scrapes a channelin the earth in which the tooth holder can travel unobstructed, and asis illustrated by the blade in contact with the earth in Figure 1. Theextensible trencher tooth 22 of my invention comprises a body 23including a lower portion 24 and an upper portion 26 or check or cap.Projecting rearwardly from the lower portion 24 is a shank 27 having atop surface 23 suitably con-formed for close abutment with the outerside of the bucket wall. Piercing the shank is a pair of apertures, suchas 29 and 30, to receive through bolts 31 and 32 respectively forfastening the shank to thebucket wall. Projecting rearwardly from theupper portion or cheek of the body is a lip 33, having an aperture 34therein to receive the'fastening 31. The portion of'the body between thelip and the shank is tapered, as 'at 36,to receive in tight engagementthe tapered portion 14 of the bucket edge, and thereby stiffening themounting of the body on the bucket edge. At the end of the body awayfrom the shank is a face 37 substantially normal to the general plane ofthe shank and extending from the lower side of the body upwardly to theupper forward end of the cheek 26.

As appears most clearly in Figure 3, the body 23 has formed therein agenerally elongated chamber 41 inclined from an opening 42 in the frontface 37 rearwardly and upwardly, as appears most clearly in Figure 3,and terminating, in a rearwall 43.; The opposite edges 44 of the chamberare bounded by the edge walls of the cap 26 or cheek portion of the bodyand serve to confine a blade 46 disposed within the chamber againstlateral or transverse motion, the lateral dimension or width of theblade being slightly less than the width of the chamber. The blade 46 isof a springy or resilient material, preferably steel, and in its new'or'original length extends from its innermost end 45 in abutment with thechamber end 43 outwardly through the opening 42 and extending stillfurther outwardly to terminate in a blade tip 47, the tip 47 being at alocation preferably below the general plane of the lower side 48 of thebody. This blade position, as may be seen by reference to Figure 1, willtend to undercut the earth so that the earth does not impinge directlyupon the face 37 or body 23 of the trencher tooth and will thus avoidthe wear on the tooth which otherwise would obtain.

The lower side 51 of the chamber, as appears in Figure 3, is defined bya generally planar surface 52 extending from the lower side 53 of theopening 42 to the rear abutment wall 43 of the chamber. The upper side56 of the chamber is generally serrated in cross-section and extendsinwardly from the upper side 61'of the opening 42 and for a shortportion 62 of its length is substantially parallel with the planarportion 52 of the lower side of the chamber. At the innermost end of theparallel portion 62, however, the chamber inclines upwardly to define asloping portion 66 or tread surface and then in serrated or steppedfashion projects inwardly and toward the lower side of the chamber toform a riser surface 67 'or abutment wall. As the riser surface 67approaches the planar portion 52 at a distance somewhat in excess of thedistance separating the parallel planar portions 62 and 52, the risersurface again inclines upwardly and rearwardly in a direction generallyparallel to the tread surface 66 and forming a tread surface 68 followedby an inwardly' jutting riser surface 69. This latter step, in turn, isfollowed by another and similar tread surface 71 and a correspondingriser surface 72. Following the riser 72, a still further tread surface73 terminates in an innermost riser surface and which is congruent withthe rear abutment wall 43.

Transversely disposed within the lower portion 24 of the body 23 is acavity 81 substantially right circular cylindrical in section andextending from one side of the body to the other. The upper portion ofthe cavity opens into the chamber 41.' Disp'osed'within the transversecavity 81is a'clamping member, generally designated 84, and most clearlyappearing in Figures 4 and 5. The clamping member 84 comprises a pair ofoppositely disposed journals 86 and 87, or flanges, substantially rightcircular cylindrical in section and of a size slightly less in diameterthan the cavity 81. Each of the journals 86 and 87 has formed in theoutermost face thereof a socket 88'to accommodate an appropriate sizeand kind of socket wrench while a square or hexagonal or other headcould be used'in place of the. socket, the

Socket provides a surface free of undesirable projections. The centralportion 89 of the clamping member, disposed between the inner faces 91and 92 of the journals is formed so thatone portion 93 of its outerperiphery is flat, the flat surface 93 coinciding with or beingco-planar with, in one position of the clamping member, the plane 52 ofthe chambers lower side 51;

The remaining portion ,94 of the outer surface of the central portion 89is cam shaped in section, as most clearly appears in Figure 3, and thesurface of the cam is roughened, such as by'knur1ing 96.' The camsurface is so shaped that as the clamping member is rotated clockwise,as appears in Figure 3, the uppermost transverse line of contact betweenthe knurled cam surface and the underneath side of the blade movesupwardly, the amount of upward motion corresponding to a predeterminedamount of rotation of the clamping member. The greater is the amount ofclockwise rotation, the more the upward deflection of the blade. It isto be noted that when the blade is disposed in the chamber, the innerfaces 91and 92 of the flanges straddle the blade and thusfthe clampingmember is prevented from. lateral translation. If necessary to removethe clamping member 84, however, removal of the'blade allows the member84'to be withdrawn. g When a new blade is to be installed, the bladesinnermost or root portion 45 is pushed inwardly through'the opening 42and into abutment with the innermost end 43 of the chamber, theoutermost tip 47 of the blade then being in the position approximatelyas shown in Figure 3. ing member 84 is-in its normal or inactiveposition,in which attitude the fiat surface 93 is substantially coplanarwith the lower or underneath surface of the blade,

the blade sliding over the flat surface 93. With the-blade in theposition shown in Figure 3, a socket wrench is inserted in the socket 88and turned clockwise so that a slight ridge 95 at the intersection ofthe flat face 93 and the knurled surface 94 bears against the bottomside of the blade. As rotation is continued the knurled surface ofthe-cam face deforms the adjacent portion of the blade more and moreupwardly until the blade assumes a somewhat bowed shape, as appears inFigure 3. Concurrently, the end of the blade is also urged inwardly witha very considerable force against the abutment wall 43 since as the camface is turned clockwise the knurled portionof the cam face bites intothe blade and forces portion 66 of the upper side of the chamber. Also,fadjacentthe lower tip of the riser surface 72 a tight engagement isobtained between the upper portion ofthe blade and the tip. Furtherrotation of the cam face causes even greater distortion of the blade andeventually forces the upper surface of the blade to come into engagementwith the lower tips of the riser surfaces 67 and 69. In this extremeposition the frictional engage-' ment between blade and chamber wallsoffers great resistance to the blades translation either toward the leftor toward the right. The frictional resistance to inward translationaugments or supplements the positive bar to movement provided by the endwall 43. In this situation the blade is held very tightly and rigidlywithin the body of the trencher tooth, and the blade is not onlyprevented from translating in either direction but also from traversingthe chamber laterally. j

As the blade becomes worn and the tip-0f the blade approaches a'position at or about the plane of the lower surface 48 of the body, theclamping member, by a socket wrench, maybe turned counter-clockwiseuntil the fl at While the blade is being inserted, the clampsurface 93is again in contact with the lower portion of the blade, the resilienceof the blade having returned the blade to its normal planar attitude andpermitting the blade to he slid along the elongated chamber in anoutward direction and into a location such that the innermost end of theblade is adjacent the riser face 72. At this juncture, the clampingmember 84 may again be rotated counter-clockwise and thus deforming theblade upwardly and wing it toward the right so that the innermost end 45of the blade comes into tight abutment with the riser surface 72, andwith the upper innermost portion of the blade bearing tightly againstthe tread surface 71. Thus as the blade becomes worn, the clampingmember may be loosened, the blade pulled outwardly to a position belowthe next outermost step, and the blade cammed into its next position.This operation is repeated each time the blade is to be extended. Figure5 shows the blade in one of these intermediate positions and illustratesthe manner in which the innermost end of the blade is deformed upwardlyand inwardly against the riser surface 69 and is also in tightengagement on its upper surface with the tread surface 68. Anyconvenient number of serrations may be used and when the blade hasbecome worn when in its outermost position, that is, in abutment withthe wall 67, the blade is discarded and a new blade inserted. As will beseen, the extensible trencher tooth of my invention permitsapproximately one-third of the original length of the blade to be wornaway before replacement is necessary and the replacement operationitself is quickly performed, with simple, readily available hand-toolsand by unskilled labor.

It has been found that by inclining the riser surfaces 67, 69, 72 and 73in such a direction that full contact between the respective risersurfaces and the root end 45 of the blade is effected when the blade isin its most deformed position, a greater blade rigidity is obtained.

As appears most clearly in Figure 3, the riser surfaces are not allexactly parallel but are at an angle with respect to each other and allof them face generally toward the opening 42 in the outer face of thebody.

What is claimed is:

An extensible trencher tooth comprising a body having formed therein anelongated chamber open at one end of said body, said chamber beingbounded by a substantially planar first side and opposite said firstside a second side formed with a plurality of steps therein, each ofsaid steps including a riser surface facing toward said open end of saidchamber, an elongated blade in said chamber, and rotatable means forurging the inner end of said blade in a direction away from said planarfirst side and toward said second side and into abutment with apredetermined one of said riser surfaces, said rotatable means includinga pair of members adjacent each edge of said blade whereby saidrotatable means is constrained against translation when said blade is insaid chamber.

References Cited in the file of this patent UNITED STATES PATENTS1,265,359 Moore May 7, 1918 1,333,852 Kittredge Mar. 16, 1920 1,834,391Edmunds Dec. 1, 1931 2,223,831 Luers Dec. 3, 1940 2,250,904 Coflman July29, 1941 2,339,128 Younie Jan. 11, 1944 FOREIGN PATENTS 12,117 NorwayAug. 10, 1903

